1. Field of the Invention
This invention relates to bubblers for converting a liquid chemical to a chemical vapor by bubbling a carrier gas through a liquid chemical.
2. Prior Art
As referred to in the Lipisko et al. U.S. Pat. No. 4,859,375, prior bubblers utilize a single carrier-gas inlet tube which is immersed in the liquid chemical and which has a single gas outlet hole positioned near the bottom level of the liquid chemical to provide a single stream of carrier-gas bubbles through the liquid chemical. Some of the liquid chemical material is vaporized by the carrier-gas to form a chemical vapor.
Bubbler chambers are formed as quartz ampules, which are fragile and which also may have problems with maintaining the seals at their glass-to-metal interfaces.
Bubbler chambers are also formed as refillable stainless steel cylinders, which are manufactured from a machined-casting body with a removable top coverplate. The top coverplate is removably sealed to the body with a gasket, providing a potential source of contamination to the chemicals within the bubbler. The temperature of the chemical liquid in these bubbler chambers is controlled by heater elements.
Spargers are devices for introducing a stream of gas into a liquid in the form of gas bubbles. As described on page 140 of the book by Robert E. Treybal entitled Mass-Transfer Operations, 3rd Edition, McGraw-Hill, 1980, a sparger with more than one orifice may be used for vessels having a diameter greater than 0.3 meters.